<head>
  <style> body { margin: 0; } </style>

  <script type="importmap">{ "imports": {
    "react": "https://esm.sh/react",
    "react-dom": "https://esm.sh/react-dom/client"
  }}</script>

<!--  <script type="module">import * as React from 'react'; window.React = React;</script>-->
<!--  <script src="../../src/packages/react-force-graph-2d/dist/react-force-graph-2d.js" defer></script>-->
</head>

<body>
  <div id="graph"></div>

  <script src="//unpkg.com/@babel/standalone"></script>
  <script type="text/jsx" data-type="module">
    import ForceGraph2D from 'https://esm.sh/react-force-graph-2d?external=react';
    import React, { useMemo, useState, useCallback } from 'react';
    import { createRoot } from 'react-dom';
    import { genRandomTree } from '../datasets/random-data.js';

    const NODE_R = 8;
    const HighlightGraph = () => {
      const data = useMemo(() => {
        const gData = genRandomTree(80);

        // cross-link node objects
        gData.links.forEach(link => {
          const a = gData.nodes[link.source];
          const b = gData.nodes[link.target];
          !a.neighbors && (a.neighbors = []);
          !b.neighbors && (b.neighbors = []);
          a.neighbors.push(b);
          b.neighbors.push(a);

          !a.links && (a.links = []);
          !b.links && (b.links = []);
          a.links.push(link);
          b.links.push(link);
        });

        return gData;
      }, []);

      const [highlightNodes, setHighlightNodes] = useState(new Set());
      const [highlightLinks, setHighlightLinks] = useState(new Set());
      const [hoverNode, setHoverNode] = useState(null);

      const updateHighlight = () => {
        setHighlightNodes(highlightNodes);
        setHighlightLinks(highlightLinks);
      };

      const handleNodeHover = node => {
        highlightNodes.clear();
        highlightLinks.clear();
        if (node) {
          highlightNodes.add(node);
          node.neighbors.forEach(neighbor => highlightNodes.add(neighbor));
          node.links.forEach(link => highlightLinks.add(link));
        }

        setHoverNode(node || null);
        updateHighlight();
      };

      const handleLinkHover = link => {
        highlightNodes.clear();
        highlightLinks.clear();

        if (link) {
          highlightLinks.add(link);
          highlightNodes.add(link.source);
          highlightNodes.add(link.target);
        }

        updateHighlight();
      };

      const paintRing = useCallback((node, ctx) => {
        // add ring just for highlighted nodes
        ctx.beginPath();
        ctx.arc(node.x, node.y, NODE_R * 1.4, 0, 2 * Math.PI, false);
        ctx.fillStyle = node === hoverNode ? 'red' : 'orange';
        ctx.fill();
      }, [hoverNode]);

      return <ForceGraph2D
        graphData={data}
        nodeRelSize={NODE_R}
        autoPauseRedraw={false}
        linkWidth={link => highlightLinks.has(link) ? 5 : 1}
        linkDirectionalParticles={4}
        linkDirectionalParticleWidth={link => highlightLinks.has(link) ? 4 : 0}
        nodeCanvasObjectMode={node => highlightNodes.has(node) ? 'before' : undefined}
        nodeCanvasObject={paintRing}
        onNodeHover={handleNodeHover}
        onLinkHover={handleLinkHover}
      />;
    };

    createRoot(document.getElementById('graph'))
      .render(<HighlightGraph />);
  </script>
</body>